Description:TECHNICAL FIELD
The present disclosure relates to the field of optical fiber cables and, in particular, relates to an optical fiber cable with embedded strength members.
BACKGROUND
Optical fiber refers to the technology and the medium for the transmission of data as light pulses along an ultrapure strand of glass, which is as thin as a human hair. For many years, optical fibers have been extensively used in high-performance and long-distance data and networking. An optical fiber cable generally has one or more optical fibers and a sheath. Further, the optical fiber cable has one or more strength members embedded in the sheath. However, water penetration through the strength members embedded in the sheath is a major concern that diminishes performance of the optical fiber cable. Generally, a bonding of a material (e.g., Ethylene Acrylic Acid (EAA)) of the sheath with a material (e.g., of Aramid Reinforcement Plastic (ARP)) of the strength members is not strong enough and tend to separate from the ARP and a bond with the Polyethylene (PE) material leaving behind a void between ARP and EAA, hence creating a passage for water ingress.
A prior art reference “US2002039869A1” discloses about mixing of a terpolymer material in the sheath material and extruding the mixture to make sheath. Another prior art reference “US2013259434A1” discloses a coating of strength members with EAA. However, none of the prior art reference discloses about improving the bonding of a material of the sheath with a material of the strength members to reduce water ingression.
Therefore, there is a need for an optical fiber cable that overcomes one or more limitation associated with the available optical fiber cables.
SUMMARY
In an aspect of the present disclosure, an optical fiber cable is disclosed. The optical fiber cable has one or more optical fibers. The optical fiber cable further has a sheath that surrounds the one or more optical fibers. The optical fiber cable further has one or more strength members. The one or more strength members are at least partially embedded in the sheath and the one or more strength members has corresponding one or more coatings of a terpolymer material.
BRIEF DESCRIPTION OF DRAWINGS
Having thus described the disclosure in general terms, reference will now be made to the accompanying figures, where:
FIG. 1 illustrates a cross-sectional view of an optical fiber cable.
FIG. 2 illustrates a cross-sectional view of another optical fiber cable.
It should be noted that the accompanying figures are intended to present illustrations of exemplary aspects of the present disclosure. These figures are not intended to limit the scope of the present disclosure. It should also be noted that accompanying figures are not necessarily drawn to scale.
DEFINITIONS
The term “optical fiber” as used herein refers to a light guide that provides high-speed data transmission. The optical fiber has one or more glass core regions and one or more glass cladding regions. The light moving through the glass core regions of the optical fiber relies upon the principle of total internal reflection, where the glass core regions have a higher refractive index (n1) than the refractive index (n2) of the glass cladding region of the optical fiber.
The term “optical fiber cable” as used herein refers to a cable that encloses one or more optical fibers.
The term “core region” of an optical fiber as used herein refers to an inner most cylindrical structure present in the optical fiber which is configured to guide the light rays inside the optical fiber.
The term “cladding region” as used herein refers to one or more layered structure covering the core of an optical fiber from the outside, which is configured to possess a lower refractive index than the refractive index of the core of the optical fiber to facilitate total internal reflection of light rays inside the optical fiber. Further, the cladding of the optical fiber may include an inner cladding layer coupled to the outer surface of the core of the optical fiber and an outer cladding layer coupled to the inner cladding from the outside.
The term “Terpolymer” as used herein refers to a chemical compound resulting from a polymer that has a molecular structure built mostly or completely from a large number of similar units bonded together. A terpolymer is a result of the copolymerization of three different monomers.
DETAILED DESCRIPTION
The detailed description of the appended drawings is intended as a description of the currently preferred aspects of the present disclosure, and is not intended to represent the only form in which the present disclosure may be practiced. It is to be understood that the same or equivalent functions may be accomplished by different aspects that are intended to be encompassed within the spirit and scope of the present disclosure.
Moreover, although the following description contains many specifics for the purposes of illustration, anyone skilled in the art will appreciate that many variations and/or alterations to said details are within the scope of the present technology. Similarly, although many of the features of the present technology are described in terms of each other, or in conjunction with each other, one skilled in the art will appreciate that many of these features can be provided independently of other features. Accordingly, this description of the present technology is set forth without any loss of generality to, and without imposing limitations upon, the present technology.
FIG. 1 illustrates a cross-sectional view of an optical fiber cable 100. The optical fiber cable 100 may have one or more strength members coated with a terpolymer material that promotes adhesion of the one or more strength members with a sheath (made up of a thermoplastic material) of the optical fiber cable, thus preventing water ingression through the gaps between the sheath and the one or more strength members. The optical fiber cable 100 may have one or more optical fibers 102 of which first through seventh optical fibers 102a-102g are shown. The optical fiber cable 100 may further have a sheath 104, and one or more strength members 106 of which first and second strength members 106a and 106b are shown.
The one or more optical fibers 102 (i.e., the first through seventh optical fibers 102a-102g) may be disposed parallel to one another along a length of the optical fiber cable 100. In some aspects of the present disclosure, the one or more optical fibers 102 may be substantially similar to one another. In other words, each of the first through seventh optical fibers 102a-102g may be substantially similar to each other. Each optical fiber of the one or more optical fibers 102 (i.e., the first through seventh optical fibers 102a-102g) may have a core (not shown), a cladding (not shown), one or more outer coating layers (not shown). The one or more optical fibers 102 (i.e., the first through seventh optical fibers 102a-102g) may be adapted to facilitate in transmission of data in the form of optical signals. Although FIG. 1 illustrates that the one or more optical fibers 102 has seven optical fibers (i.e., the first through seventh optical fibers 102a-102g), it will be apparent to a person skilled in the art that the scope of the present disclosure is not limited to it. In various other aspects, the one or more optical fibers 102 may have any number of optical fibers, without deviating from the scope of the present disclosure. In such a scenario, each optical fiber is configured to perform one or more operations in a manner similar to the operations of the first through seventh optical fibers 102a-102g as described above.
The sheath 104 may be an outermost layer of the optical fiber cable 100 that may provide support, strength, and insulation to the optical fiber cable 100. Further, the sheath 104 may facilitate to reduce abrasion and to provide the optical fiber cable 100 with extra protection against external mechanical effects such as crushing. In some aspects of the present disclosure, the sheath 104 may be made up of a material a thermoplastic material such as, but not limited to, Polyethylene (PE) material, Low-Smoke Zero-Halogen (LSZH) material, Polyvinyl Chloride (PVC) material, polyamide (PA) material, and the like. Aspects of the present disclosure are intended to include and/or otherwise cover any type of the material for the sheath 104, known to a person having ordinary skill in the art, without deviating from the scope of the present disclosure.
The one or more strength members 106 (i.e., the first and second strength members 106a and 106b) may be provided to increase a tensile strength of the optical fiber cable 100 that plays a vital role during an installation process of the optical fiber cable 100. The one or more strength members 106 (i.e., the first and second strength members 106a and 106b) may be at least partially embedded in the sheath 104. In some aspects of the present disclosure, the one or more strength members 106 (i.e., the first and second strength members 106a and 106b) may be fully embedded in the sheath 104. In some aspects of the present disclosure, the first and second strength members 106a and 106b may be made up of a material such as, but not limited to, a Fibre-reinforced plastic (FRP), an Aramid Reinforcement Plastic (ARP), steel rods, and the like. Aspects of the present disclosure are intended to include and/or otherwise cover any type of the material for the first and second strength members 106a and 106b, including known, related, and later developed materials. It will be apparent to a person skilled in the art that the one or more strength members 106 is shown to have two strength members (i.e., the first and second strength members 106a and 106b) to make the illustration concise and clear and should not be considered as a limitation of the present disclosure. In various other aspects, the one or more strength members 106 may have any number of strength members, without deviating from the scope of the present disclosure. In such a scenario, each strength member of the one or more strength members 106 is adapted to serve one or more functionalities in a manner similar to the functionalities of the first and second strength members 106a and 106b as described above.
The one or more strength members 106 of which the first and second strength members 106a and 106b are shown may have corresponding one or more coatings 108 of which first and second coatings 108a and 108b are shown. Specifically, the first strength member 106a may have the first coating 108a and the second strength member 106b may have the second coating 108b.
The one or more coatings 108 (i.e., the first and second coatings 108a and 108b) may be made up of a terpolymer material. In some aspects of the present disclosure, the terpolymer material may be extruded over the one or more strength members 106. Specifically, the terpolymer material may be in the form of granules that may be melted and extruded over the one or more strength members 106 to form the one or more coatings 108. In other words, the terpolymer material may be in the form of granules that may be melted and extruded over the first and second strength members 106a and 106b to form the first and second coatings 108a and 108b. In some aspects of the present disclosure, the terpolymer material may be extruded over the first and second strength members 106a and 106b to form the first and second coatings 108a and 108b at an extrusion temperature that may be in a range of 140 Degree Celsius (°C) to 160 °C. In some aspects of the present disclosure, the terpolymer material has a melt flow rate of greater than 5 grams per 10 minutes at 190 Degree Celsius (°C) per 2.16 Kilograms (KG). Specifically, a higher melt flow rate i.e., greater than 5g/10min at 190 °C/2.16 kg may facilitate in extruding a thin coating of the material on the one or more strength members 106. On the other hand, a melt flow rate of less than 5g/10min at 190 °C/2.16 kg can adversely affect an extrusion speed and a coating thickness of the one or more coating 108.
In some aspects of the present disclosure, the terpolymer material comprises of, an ethylene (E) terpolymer comonomer, a t-butylacrylate (tBA) terpolymer comonomer, and an acrylic acid (AA) terpolymer comonomer. In some aspects of the present disclosure, the terpolymer material may have a t-butylacrylate (tBA) comonomer content of at least 7%. Specifically, below this 7 %, the adhesion chemistry will not be strong to prevent water leak, thus, the terpolymer material may have the tBA comonomer content of at least 7%. In some aspects of the present disclosure, the terpolymer material has acrylic acid (AA) comonomer content of at least 4%. Specifically, below 4 %, the adhesion chemistry will not be strong to prevent water leak, the terpolymer material has the AA comonomer content of at least 4%. In some aspects of the present disclosure, the terpolymer material has a coefficient of friction (CoF) of greater than 0.8. Specifically, a higher CoF i.e., greater than 0.8 may prevent slippage of the one or more strength members 106 within the sheath 104 during bending and/or handling operations. In some aspects of the present disclosure, the first and second coatings 108a and 108b may have a thickness in a range of 15 micrometres (µm) to 30 µm. Specifically, when the thickness of the first and second coatings 108a and 108b is below 15 µm, the first and second coatings 108a and 108b may not be sufficient to provide a strong adhesion with the sheath 104. On the other hand, when the thickness of the first and second coatings 108a and 108b is above 30 µm, diameters of the one or more strength members 106 will increase, which will increase a thickness of the sheath 104 and thus may increase a diameter and a weight of the optical fiber cable 100 which is not desirable. Thus, the thickness of the first and second coatings 108a and 108b is selected in the range of 15 µm to 30 µm. The first and second coatings 108a and 108b may facilitate in stoppage of water ingression through the gaps between the one or more strength members 106 and the sheath 104 of the optical fiber cable 100.
The optical fiber cable 100 may have may further have one or more additional layers (not shown) disposed between optical fibers 102 and the sheath 104. For example, the one or more additional layers may have one or more layers of water blocking tape (WBT), one or more layers of water swellable yarn (WSY), one or more layers of tensile yarns (e.g., an aramid, a glass roving yarn), one or more layers of armouring (e.g., a dielectric armouring such as a Fibre Reinforced Plastic (FRP), a metal armouring such as steel tape and/or steel rods). In some aspects of the present disclosure, the one or more optical fibers 102 may be enclosed within one or more thermoplastic enclosures (not shown) inside the sheath 104 such as buffer tubes, micromodules, tight buffers.
FIG. 2 illustrates a cross-sectional view of another optical fiber cable 200. The optical fiber cable 200 may be substantially similar to the optical fiber cable 100 of FIG. 1 with like elements referenced with like reference numerals. However, the optical fiber cable 200 has one or more optical fiber ribbons 202 having the one or more optical fibers 102 and the one or more strength members 106 of the optical fiber cable 200 may have four strength members (i.e., the first and second strength members 106a and 106b and third and fourth strength members 204a and 204b). The optical fiber cable 100 may further have the sheath 104.
The one or more optical fiber ribbons 202 may have first through seventh optical fiber ribbons 202a-202g). The one or more optical fiber ribbons 106 (i.e., the first through seventh optical fiber ribbons 202a-202g) may be disposed parallel to one another along a length of the optical fiber cable 200. In some aspects of the present disclosure, the one or more optical fiber ribbons 202 may be, but not limited to, a flat ribbon, an intermittently bonded ribbon, and the like. In some aspects of the present disclosure, the one or more optical fiber ribbons 202 may be substantially similar to one another. Each optical fiber ribbon of the one or more optical fiber ribbons 202 may have the one or more optical fibers 102 (as shown in FIG. 1)). Although FIG. 2 illustrates that the one or more optical fiber ribbons 202 has seven optical fiber ribbons (i.e., the first through seventh optical fiber ribbons 202a-202g), it will be apparent to a person skilled in the art that the scope of the present disclosure is not limited to it. In various other aspects, the one or more optical fiber ribbons 202 may have any number of optical fiber ribbons, without deviating from the scope of the present disclosure.
The one or more strength members 106 (i.e., the first and second strength members 106a and 106b and the third and fourth strength members 204a and 204b) may be provided to increase a tensile strength of the optical fiber cable 200 that plays a vital role during an installation process of the optical fiber cable 200. The one or more strength members 106 (i.e., the first and second strength members 106a and 106b and the third and fourth strength members 204a and 204b) may be at least partially embedded in the sheath 104. In some aspects of the present disclosure, the one or more strength members 106 (i.e., the first and second strength members 106a and 106b and the third and fourth strength members 204a and 204b) may be fully embedded in the sheath 104. In some aspects of the present disclosure, the first and second strength members 106a and 106b and the third and fourth strength members 204a and 204b may be made up of a material such as, but not limited to, a Fibre-reinforced plastic (FRP), an Aramid Reinforcement Plastic (ARP), steel rods, and the like. Aspects of the present disclosure are intended to include and/or otherwise cover any type of the material for the first and second strength members 106a and 106b and the third and fourth strength members 204a and 204b, including known, related, and later developed materials. It will be apparent to a person skilled in the art that the one or more strength members 106 is shown to have four strength members (i.e., the first and second strength members 106a and 106b and the third and fourth strength members 204a and 204b) to make the illustration concise and clear and should not be considered as a limitation of the present disclosure. In various other aspects, the one or more strength members 106 may have any number of strength members, without deviating from the scope of the present disclosure. In such a scenario, each strength member of the one or more strength members 106 is adapted to serve one or more functionalities in a manner similar to the functionalities of the first and second strength members 106a and 106b and the third and fourth strength members 204a and 204b as described above.
The one or more strength members 106 of which the first and second strength members 106a and 106b may have corresponding the one or more coatings 108 of which first and second coatings 108a and 108b are shown. Specifically, the first strength member 106a may have the first coating 108a and the second strength member 106b may have the second coating 108b. The first and second coatings 108a and 108b may be made up of a terpolymer material. The terpolymer material may be extruded over the first and second strength members 106a and 106b, respectively. Further, the third and fourth strength members 204a and 204b may the one or more coatings 108 i.e., third and fourth coatings 206a and 206b, respectively. The third and fourth coatings 206a and 206b may be made up of a terpolymer material. In some aspects of the present disclosure, the terpolymer material may be extruded over the third and fourth strength members 204a and 204b, respectively. Specifically, the terpolymer material may be in the form of granules that may be melted and extruded over the one or more strength members 106 to form the one or more coatings 108. In some aspects of the present disclosure, the terpolymer material may be extruded over the first and second strength members 106a and 106b and the third and fourth strength members 204a and 204b to form the first and second coatings 108a and 108b and the third and fourth coatings 206a and 206b at an extrusion temperature that may be in a range of 140 Degree Celsius (°C) to 160 °C. In some aspects of the present disclosure, the terpolymer material has a melt flow rate of greater than 5 grams per 10 minutes at 190 Degree Celsius (°C) per 2.16 Kilograms (Kg). Specifically, a higher melt flow rate i.e., greater than 5g/10min at 190 °C/2.16 kg may facilitate in extruding a thin coating of the material on the one or more strength members 106. On the other hand, a melt flow rate of less than 5g/10min at 190 °C/2.16 kg can adversely affect an extrusion speed and a coating thickness of the one or more coating 108.
In some aspects of the present disclosure, the terpolymer material comprises, an ethylene (E) terpolymer comonomer, a t-butylacrylate (tBA) terpolymer comonomer, and an acrylic acid (AA) terpolymer comonomer. In some aspects of the present disclosure, the terpolymer material may have a t-butylacrylate (tBA) comonomer content of at least 7%. Specifically, below this 7 %, the adhesion chemistry will not be strong to prevent water leak, thus, the terpolymer material may have the tBA comonomer content of at least 7%. In some aspects of the present disclosure, the terpolymer material has acrylic acid (AA) comonomer content of at least 4%. Specifically, below 4 %, the adhesion chemistry will not be strong to prevent water leak, the terpolymer material has the AA comonomer content of at least 4%. In some aspects of the present disclosure, the terpolymer material has a coefficient of friction (CoF) of greater than 0.8. Specifically, a higher CoF i.e., greater than 0.8 may prevent slippage of the one or more strength members 106 within the sheath 104 during bending and/or handling operations. In some aspects of the present disclosure, the first, second, third and fourth coatings 108a, 108b, 206a and 206b may have a thickness in a range of 15 micrometres (µm) to 30 µm. Specifically, when the thickness of the first, second, third and fourth coatings 108a, 108b, 206a and 206b is below 15 µm, the first, second, third and fourth coatings 108a, 108b, 206a and 206b may not be sufficient to provide a strong adhesion with the sheath 104. On the other hand, when the thickness of the first, second, third and fourth coatings 108a, 108b, 206a and 206b is above 30 µm, diameters of the one or more strength members 106 will increase, which will increase a thickness of the sheath 104 and thus may increase a diameter and a weight of the optical fiber cable 200 which is not desirable. Thus, the thickness of the third and fourth coatings 108a, 108b, 206a and 206b is selected in the range of 15 µm to 30 µm. The first and second coatings 108a and 108b and the third and fourth coatings 206a and 206b may facilitate in stoppage of water ingression through the gaps between the one or more strength members 106 and the sheath 104 of the optical fiber cable 200.
Thus, the optical fiber cable 100, 200 of the present disclosure have one or more strength members 106 coated with a terpolymer material that promotes adhesion of the one or more strength members 106 with the sheath 104 (made up of a thermoplastic material), which in turn prevents water ingression through the gaps between the sheath 104 and the one or more strength members 106.
The foregoing descriptions of specific aspects of the present technology have been presented for the purpose of illustration and description. They are not intended to be exhaustive or to limit the present technology to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The aspects were chosen and described in order to best explain the principles of the present technology and its practical application, to thereby enable others skilled in the art to best utilize the present technology and various aspects with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present technology.
While several possible aspects of the invention have been described above and illustrated in some cases, it should be interpreted and understood as to have been presented only by way of illustration and example, but not by limitation. Thus, the breadth and scope of a preferred aspect should not be limited by any of the above-described exemplary aspects. , Claims:I/We Claim(s):
1. An optical fiber cable (100, 200) comprising:
one or more optical fibers (102);
a sheath (104) that surrounds the one or more optical fibers (102); and
one or more strength members (106), where (i) the one or more strength members (106) are at least partially embedded in the sheath (104) and (ii) the one or more strength members (106) has corresponding one or more coatings (108) of a terpolymer material.

2. The optical fiber cable (100, 200) of claim 1, where the terpolymer material comprises of, an ethylene (E) terpolymer comonomer, a t-butylacrylate (tBA) terpolymer comonomer, and an acrylic acid (AA) terpolymer comonomer.

3. The optical fiber cable (100, 200) of claim 2, where the terpolymer material has a tBA comonomer content of at least 7%.

4. The optical fiber cable (100, 200) of claim 2, where the terpolymer material has an AA comonomer content of at least 4%.

5. The optical fiber cable (100, 200) of claim 1, where one or more coatings (108) has a thickness in a range of 15 micrometres (µm) to 30 µm.

6. The optical fiber cable (100, 200) of claim 1, where the terpolymer material is extruded over the one or more strength members (106) to form the one or more coatings (108).

7. The optical fiber cable (100, 200) of claim 1, where the one or more strength members (106) is at least one of a Fibre-reinforced plastic (FRP), an Aramid Reinforcement Plastic (ARP), and steel rods.

8. The optical fiber cable (100, 200) of claim 1, where the terpolymer material has a coefficient of friction (CoF) of greater than 0.8.

9. The optical fiber cable (100, 200) of claim 1, where the terpolymer material has a melt flow rate of greater than 5 grams per 10 minutes at 190 Degree Celsius (°C) per 2.16 Kilograms (Kg).